This may seem like I have hit my head and just do not know how the system works, but I am nervous, so I will ask regardless:
I am a two-generation legacy at Yale. My sister is a current sophomore and my grandfather, a very involved alum, attended. I applied EA this year, just as my sister did a few years back. My GPA is notably higher than hers: she was a B+/an occasional A- student during a few semesters, while I have straight A’s across the board. Also, I am taking AP math (she only went through regular precal) and I spent my junior year abroad in Spain. She was deferred then later accepted in March. However, I just received my fall term grades, and one of my classes was very difficult for me. It was my very first time taking an advanced/AP class in this discipline because my school in Spain did not offer APs (only in Spanish literatrue and language) and I was a new sophomore at my school the year before, so I had to take regular level chemistry as I had already taken biology. In short, in order for you to take advanced biology at my school, you need to have taken chemistry before, but I had taken biology, so I had to take regular chemistry. I got a B in this class this term, compared to my other A’s. I am worried that this will bring down my application. I know that if you are are to get a B, it is best to get one freshman or sophomore year, so I am freaking out that having one at the very end of my virtually perfect high school academic career will be a cause for concern among the admissions committee. My school does indeed send these grades to early action/decision colleges once they are finalized, which happened about a week ago. Does anyone have any expertise or knowledge on this? Having some mental peace during these next 2 weeks couldn’t hurt. 
You won’t be rejected because of one B.
lmao dude, Yale looks for wayyyyyyyyyyyy more than one B, they couldn’t care less because grades and SAT are literally less than 10% of what they look for (just throwing out a number, but you get the point). They look for people with passion to change the world, and they like for this passion to be demonstrated in ECs. Also, have perfect grades doesn’t separate you; literally everyone from my school who applied REA or ED to an ivy has near perfect grades and SAT (my school might be skewed tho, we have 42 NMF this year, and we’ve only had 1 person get into Yale each year on average). The people who get into Yale from my school in the past few years usually have significant awards such as isef/siemens and/or they’ve made a significant impact on the community by raising 30k for their nonprofit or something similar. I’m guessing over 50% of Yale REA applicants have near perfect grades or SAT. So don’t worry about that one B, it won’t have an impact, if you get rejected it will be because of something else, probably ECs or essays. Good Luck.
Did your sister have some sort of special talent, something about her that Yale would have found compelling, or is there reason to believe that she had a terrific application in all respects other than the transcript? If none of these is true, I would guess that she wouldn’t be at Yale but for her grandfather, who sounds well-connected there. The development office is likely aware you’ve applied, but he should make sure.
Based on the limited detail you’ve provided, you sound like you have a better profile than your sister (assuming, again, that there wasn’t something truly outstanding about her that you haven’t mentioned), so, assuming that your grandfather is at least as important to Yale now as when she applied, I’d feel cautiously optimistic about your chances, and I don’t think the B is going to matter a lot.
I doubt you’ll be rejected early, but be prepared to be deferred like your sister - anecdotally, I see a lot of OK-but-not-tip-top connected legacies at Yale and its peers get deferred and then admitted, because the school would rather use its early spots on the strongest candidates and takes for granted that the family will forgive them when the applicant eventually gets in.
@DeepBlue86 my sister was the head of 3 clubs in high school and also interned with Sen. Blumenthal in DC for a month during her junior year summer. She was a very active member of her community, and her admissions rep remarked that her authenticity really shone through in her essays.
The area where I attend school is pretty immigrant-heavy. Taking my second language that I acquired from my time abroad and determined to use it back in the US, I currently tutor Latin immigrants in English at a local public high school. I also am the head of the Jewish Student Union at my school, and after the attack in Pittsburgh, I organized an open forum where my peers and faculty could express their thoughts, concerns, etc. I have also organized other talks—which I keep open to people of all faiths—to promote religious conversation, appreciation, and diversity on campus. I also studied at UChicago this summer and did research with a professor of molecular engineering. Additionally, I run XC and track and field, and work at a restaurant near my hometown as a waiter. I hope this information helps give you a clearer picture.
While I do not have as many ECs as my sister, or as many as a lot of applicants, the 4 or so I do participate in are ones I am very passionate about, and I spend a lot of time on them. I really emphasized my passion for these activities in my essays, while not repeating already established dimensions of my personality/self. I have heard that 4 or 5 activities that you are passionate about is better than 10 that you spend little to no time on. I filled 8 of the 10 EC slots on the common app, though, so it is not as though I have none.
I do not know if test scores matter, but I have a 33 on my ACT (a little low, I know, but I hope to take it once more for the regular admissions cycle) and I got a 5 on my Spanish AP (my school in Spain did not offer many APs, only Spanish Lit and Lang). At my US school, sophomores cannot take APs. We actually do not even have the AP system anymore. We have “CL,” which stands for “college level”. In short, my school believes that the AP system is socio-ecomonically biased, as there are many kids at my school who cannot afford to take 5 AP tests. They also wanted more flexibility in the curriculum. Kids can still take the APs, but they are not promised that they will be totally prepared for the exams. This is true for all subjects besides math.
I also had art history professor and curator of the Yale Art Gallery write on my behalf. He is a dear friend of my grandfather, and he has known me for awhile. This serves as my third supplemental letter.
I do not have as many ECs as my sister and many other applicants, but I am very passionate about the ones I participate in and lead. I believe that having 5 or 6 that you are passionate about is better than 10 that you spend little to no time on. I did fill out 8 of the 10 EC slots on the common app, so it is not as though I have none. I do not debate, I do not participate in student council, I do not write for the school paper, but I try to advance community life through organizations or subjects I am passionate about.
I also have a 33 on my ACT (a little low, I know, but I am going to take it once more in December for the regular admissions cycle) and a 5 on my Spanish AP exam. This was the only AP offered by my school in Spain, and sophomores at the US school cannot take APs. For freshman year, I went to a junior boarding school (a school that ends in 9th grade and has boarding students beginning in 6th grade) and they do not offer any APs. So, my hands are pretty tied for my AP situation. I worry that this will be a cause for concern as well. I simply did not have the resources to take as many AP classes as my peers because I went abroad, something rarely done by high school students. I am taking 4 APs this year, though, and my college advisor says that she explains the situation students who study abroad face in terms of course load in her counselor report, and that colleges understand due to their relationship with the program I studied through.
An art history professor and curator of the Yale Art Gallery also wrote on my behalf. He is a dear friend of my grandfather and of my family, and I have known him for awhile. This serves as my third supplemental letter.
The one B is not going to make the difference. What were your sister’s test scores? I am only asking to gauge the potential legacy/development pull that your grandfather might have.
@ctgirl2019, regardless of the legacy status, having an interesting high school background such as you do has to help. I wouldn’t worry too much as long as you did your best with the resources you had, and have interesting perspectives to share with the admissions committee. Colleges are more interested in those attributes than they are in selecting a bunch of cookie-cutter applicants with the same background.
@BKSquared my sister had a 32 on her ACT. And she got a 5 on English Lit AP, 3 on French, and I believe 4 on Euro.
@BKSquared - based on all this, I think you’ll agree with me that, if OP’s sister was otherwise unhooked, she has a grandfather who is important to Yale… 
Since your sister was deferred, OP, where else did she get in RD? From what you’ve disclosed, I doubt she was admitted to many of the schools usually grouped with Yale.
I’m going to guess you’ll be admitted, OP - but maybe not early. Try to get that ACT up and make it easier for Yale if you get deferred.
Without really knowing the specifics of the subjectives (LoR’s, essays and how the AO perceives the EC’s), looks like you compare favorably with your sister. Grandfather may have some pull given the 32 ACT of your sister. Best of luck!
Get those other apps started so you can enjoy your winter break whether Yale works out or not! Good luck!
@DeepBlue86 my sister was admitted to 6 of the 11 schools she applied to: Kenyon, Macalester, NYU, American, GW, and Yale. Deferred by Barnard, Hamilton, and Bates. Rejected by columbia and middlebury. She didn’t apply to many reaches.
Will my current ACT get my rejected? I know it’s on the lower end of their average, but I don’t believe it will be a reason for rejection, right?
Thank you, @ctgirl2019 - to be honest, none of that is terribly surprising.
Good luck to you, and - my two cents - if you’re fortunate enough to be admitted to Yale and enroll, think of the dying words of Captain Miller (Tom Hanks) to Private Ryan (Matt Damon): “Earn this…earn it”. Then do great things there.
The 33 puts you near the middle (32-35 are the 25th to 75th percentiles). Given your sister’s ACT and admissions results, I tend to agree with @DeepBlue86 that it is likely that your grandfather has greater than average legacy pull. I also agree that if you are deferred, I’d work as many levers as you can, from improving test scores, keeping up your grades, updating the AO with any achievements and having your grandfather work his development officer.
I wanted to thank OP for sharing these datapoints, which I think are valuable to legacy applicants. Kids haven’t gone through yet but I can already tell that not all legacies need to clear the same bar. Important for families to realize this, particularly if the familial tie to the school is of the ordinary variety.
@toandfro While my connection is strong, my sister is a qualified student, although maybe not numbers-wise. She is involved, proactive, dedicated, and truly an authentic human. She brings different things to the table that the “standard” Yale applicant does not, that is, the straight-A scholar with the perfect test scores. Yale looks for different students, not just the academic stars. I know of a C student who was admitted. He was no athlete, no legacy, but rather an extremely compelling person. It truly varies, and I assure you that while the connection helped, it was by no means the only reason she was admitted. Or at least I like to believe so.
@BKSquared @DeepBlue86 thank you for your continuous replies. It has helped me to organize all of the data. Although my test scores need improving, and given I had to do all of the testing this fall as my school in Spain did not offer testing, I hope things work out. However, it is frustrating to think that a lower test score could get me deferred. Nonetheless, deferal is not rejection, and not all hope will be lost. I hope my academic success and extra curricular efforts aid me as much as I hope they will. Fingers crossed for eventual success!
Additionally, my grandfather has talked with his officer and told him I am applying, that it is important to the family, that HE believes I am qualified (I put the “he” in caps as that is completely subjective and I am not trying to raise my status by any means), and so forth. What will come, will come! We shall see.